Cleveland's top cop today described the legal loophole which could see thousands of speeding convictions overturned as a "tragedy".

And he appealed to motorists to accept their fines despite the "legal technicality" which may render them worthless.

Chief Constable Sean Price was speaking out as the row over the use of illegal speed signs across Teesside escalated.

The Gazette revealed on Tuesday how speeding prosecutions against two North Yorkshire police officers were dropped on legal advice.

The pair were clocked last summer on the A171 near Birk Brow under Cleveland's controversial Safety Camera scheme which snares thousands of speeding motorists every month.

But they escaped punishment after it emerged many of the signs used to mark out camera enforcement zones - specifically those with a yellow background surrounded by a black border - are not legally valid under the Road Traffic Regulation Act.

Council chiefs have already started work on replacing the rogue signs, but fears are mounting that thousands of drivers will now challenge their convictions.

Chief Constable Price said: "I think it is a legally absurd principle that speeding fines are to be escaped because of a legal technicality."

The meaning of the signs was clear and the 50mph limit had dramatically reduced accidents on a road deemed an accident blackspot, he said.

"It is a tragedy that minor differences in the make-up of the sign deems it unlawful," he said.

"I do think it is particularly unfortunate the defendants were serving police officers and would emphasise we only discontinued proceedings following legal advice."

Yesterday, Redcar and Cleveland Council chief executive Colin Moore called on North Yorkshire Chief Constable Della Cannings to take disciplinary action against the two officers, PCs Andrew Macfarlane and David Burlingham.

Now some of those caught up in the speeding blitz are looking into challenging their fines and penalty points.